Sorafenib (BAY 43-9006) is a novel, orally bioavailable agent that targets downstream effectors in the Ras signaling pathway (a key dysregulated pathway in NF1). It has thus a strong scientific rationale for evaluation in NF1 related tumors. Dermal neurofibromas occur in nearly every individual with NF1, and are a significant cosmetic problem and a major cause of morbidity. This protocol will 1) quantify the growth of dermal neurofibromas in NF1 with 3 different imaging modalities 2) use an innovative gene expression method to